Multi-layered information recording medium, reproduction apparatus, recording apparatus, reproduction method, and recording method

ABSTRACT

A multi-layered information recording medium comprising a plurality of recording layers, a user data area for recording user data, provided in at least two of the plurality of recording layers, and a defect list storing area for storing a defect list. When at least one defective area is detected in the user data area, the defect list is used to manage the at least one defective area.

This application is a continuation application of U.S. patentapplication Ser. No. 11/382,517 filed on May 10, 2006, which is adivisional of U.S. application Ser. No. 10/339,630 filed Jan. 9, 2003,now U.S. Pat. No. 7,123,556, the entire disclosures of which areincorporated herein by reference, and is related to co-pending siblingU.S. application Ser. Nos. 11/382,519, 11/382,520, and 11/382,522 allfiled on May 10, 2006, and U.S. application Ser. Nos. ______ (Docket No.OKUDP0182USE), ______ (Docket No. OKUDP0182USF) and ______ (Docket No.OKUDP0182USH), all filed concurrently herewith.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multi-layered information recordingmedium comprising at least two recording layers, a reproductionapparatus, a recording apparatus for use with the multi-layeredinformation recording medium, a reproduction method for reproducinginformation from the multi-layered information recording medium, and arecording method for recording information in the multi-layeredinformation recording medium.

2. Description of the Related Art

A typical information recording medium which has a sector structure isan optical disc. In recent years, AV data, such as audio data, videodata, and the like, has been digitalized, and accordingly, an opticaldisc having a higher recording density and a larger capacity has beendemanded. Providing a plurality of recording layers is useful inincreasing the capacity of a disc. For example, the capacity of aread-only DVD has been increased about two times by providing tworecording layers to the DVD.

FIG. 1 shows a structure of a typical optical disc medium 1 including atrack 2 and sectors 3. On the optical disc medium 1, the track 2 isturned multiple times in a spiral arrangement. The track 2 is dividedinto a large number of small sectors 3. Regions formed on the discmedium 1 are roughly classified into a lead-in area 4, a user data area8, and a lead-out area 6. Recording or reproduction of user data isperformed on the user data area 8. The lead-in area 4 and the lead-outarea 6 are provided as margins such that an optical head (not shown) canappropriately follow a track even if overrunning of the optical headoccurs when the optical head approaches an end portion of the user dataarea 8. The lead-in area 4 includes a disc information area which storesparameters necessary for accessing the disc medium 1. Physical sectornumbers (hereinafter, abbreviated as “PSN(s)”) are assigned to thesectors 3 in order to identify the respective sectors 3. Further,consecutive logical sector numbers (hereinafter, abbreviated as“LSN(s)”) which start with 0 are assigned to the sectors 3 included inthe user data area 8 such that a high level apparatus (not shown) suchas a host computer identifies the respective sectors 3.

FIG. 2 illustrates a principle of reproduction of data from a read-onlyoptical disc 30 having two recording layers. Here, production of theread-only optical disc 30 of FIG. 2 is briefly described. Grooves areformed on transparent substrates 31 and 32 so as to form spiral tracks.Over the grooved surfaces of the substrates 31 and 32, recording layers33 and 34 are attached so as to cover the grooved surfaces,respectively. The substrates 31 and 32 are attached together so as tosandwich a transparent light-curable resin 35 between the recordinglayers 33 and 34, thereby obtaining a single read-only optical disc 30.In this specification, for convenience of description, in FIG. 2, arecording layer 34 closer to the incoming laser light 38 is referred toas a first recording layer 34; whereas the other recording layer 33 isreferred to as a second recording layer 33. The thickness andcomposition of the first recording layer 34 are adjusted such that thefirst recording layer 34 reflects a half of the incoming laser light 38and transmits the other half of the incoming laser light 38. Thethickness and composition of the second recording layer 33 are adjustedsuch that the second recording layer 33 reflects all of the incominglaser light 38. An objective lens 37 for converging the laser light 38is moved toward or away from the read-only optical disc 30 such that theconvergence point (beam spot) 36 of the laser light 38 is placed on thefirst recording layer 34 or the second recording layer 33.

FIGS. 3A, 3B, 3C and 3D show tracks of two recording layers 41 and 42 ofa read-only DVD, which are called parallel paths, and the reproductiondirection and sector numbers. FIG. 3A shows a spiral groove pattern ofthe second recording layer 42. FIG. 3B shows a spiral groove pattern ofthe first recording layer 41. FIG. 3C shows the reproduction directionin user data areas 8 provided on the recording layers 41 and 42. FIG. 3Dshows sector numbers assigned to the recording layers 41 and 42.

Now, consider the read-only DVD disc is rotated clockwise when it isviewed from the back face side of the disc in the direction along whichlaser light comes onto the disc, i.e., when it is viewed from the backside of the sheets of FIGS. 3A and 3B. In this case, the laser lightmoves along the track 2 from the inner periphery to the outer peripheryof the recording layers 41 and 42. In the case where user data issequentially reproduced along the reproduction direction shown in FIG.3C, reproduction is first performed from the innermost periphery to theoutermost periphery of the user data area 8 of the first recording layer41. Then, reproduction is performed from the innermost periphery to theoutermost periphery of the user data area 8 of the second recordinglayer 42. The user data areas 8 of the first and second recording layers41 and 42 are sandwiched by the lead-in area 4 and the lead-out area 6such that an optical head can appropriately follow the track 2 even ifoverrunning of the optical head occurs. As shown in FIG. 3D, the PSNsand LSNs of each of the recording layers 41 and 42 are incrementallyassigned along the reproduction direction. The PSNs do not necessarilyneed to start with 0 in view of convenience of disc formation. Further,the PSNs do not necessarily need to be continuously assigned between thefirst and second recording layers 41 and 42 (for example, a valuecorresponding to the layer number may be provided at the first locationof each sector number). As LSNs, consecutive numbers which start with 0are assigned to all of the user data areas 8 included in the opticaldisc. That is, in the user data area 8 of the first recording layer 41,the LSN at the innermost periphery is 0, and increases by ones towardthe outermost perimeter. The LSN at the innermost periphery of the userdata area 8 of the second recording layer 42 is a number obtained byadding 1 to the maximum LSN of the first recording layer 41. The LSN ofthe second recording layer 42 also increments by ones toward theoutermost perimeter.

FIGS. 4A, 4B, 4C and 4D show tracks of two recording layers 43 and 44 ofa read-only DVD, which is called an opposite path arrangement, and thereproduction direction and sector numbers. FIG. 4A shows a spiral groovepattern of the second recording layer 44. FIG. 4B shows a spiral groovepattern of the first recording layer 43. FIG. 4C shows the reproductiondirection in user data areas 8 provided on the recording layers 43 and44. FIG. 4D shows sector numbers assigned to the recording layers 43 and44.

Now, consider the read-only DVD disc is rotated clockwise when it isviewed from the back face side of the disc in the direction along whichlaser light comes onto the disc, i.e., when it is viewed from the backside of the sheets of FIGS. 4A and 4B. In this case, the laser lightmoves along the track 2 from the inner periphery to the outer peripheryin the first recording layer 43, but from the outer periphery to theinner periphery in the second recording layer 44. In the case where userdata is sequentially reproduced along the reproduction direction shownin FIG. 4C, reproduction is first performed from the innermost peripheryto the outermost periphery of the user data area 8 of the firstrecording layer 43, and then, reproduction is performed from theoutermost periphery to the innermost periphery of the user data area 8of the second recording layer 44. The user data area 8 of the firstrecording layer 43 is sandwiched by the lead-in area 4 and a middle area7 such that an optical head can appropriately follow the track 2 even ifoverrunning of the optical head occurs. The user data area 8 of thesecond recording layer 44 is sandwiched by the middle area 7 and thelead-out area 6. The function of the middle area 7 is the same as thatof the lead-out area 6. As shown in FIG. 4D, the PSNs and LSNs of eachof the recording layers 43 and 44 are incrementally assigned along thereproduction direction as in the above-described parallel paths, exceptthat the relationship between the sector numbers and the radialdirection is changed because the spiral direction of the track 2 of thesecond recording layer 44 is inverse to the spiral direction of thetrack 2 of the first recording layer 43. In the user data area 8 of thefirst recording layer 43, the LSN is 0 at the innermost periphery, andincrements by ones toward the outer periphery. The LSN at the outermostperiphery in the user data area 8 of the second recording layer 44 is anumber obtained by adding 1 to the maximum LSN in the user data area 8of the first recording layer 43, and increments by ones toward theinnermost perimeter.

Above, read-only optical discs have been described. Now, featuresspecific to a rewritable optical disc are described. Such featuresresult from the fact that requirements on a margin for a recordingoperation are more severe than that for a reproduction operation.

FIG. 5A shows an area layout of a typical rewritable disc 45. Therewritable disc 45 includes only one recording layer. A lead-in area 4of the rewritable disc 45 includes a disc information area 10 and an OPC(Optimum Power Calibration) area 11, and a defect management area 12.The lead-out area 6 includes another defect management area 12. A userdata area 8 and a spare area 13 are provided between a lead-in area 4and a lead-out area 6.

A disc information area 10 stores disc information regarding aparameter(s) or a format necessary for recording/reproduction of data ofthe optical disc. The disc information area 10 is also included in aread-only optical disc, but the disc information area 10 of theread-only optical disc includes nothing important other than a formatidentifier used for identifying the optical disc. On the other hand, ina rewritable optical disc, specific recommended values for thecharacteristics of the laser light used for recording, such as laserpower, pulse width, and the like, are stored for each generated markwidth. The disc information area 10 is a read-only area in whichinformation is typically written at the time of production of the disc.In the rewritable disc 45, pits are formed in the disc surface as in aDVD-ROM or a CD-ROM. (There is a recording principle different from sucha “pit” recording principle. For example, in a CD-RW, information isembedded in a meandering pattern (called “wobble”) of a groove.)

The OPC area 11 is provided for optimally adjusting the recording powerof laser light. A disc manufacturer stores recommended laser parametersfor a recording operation in the disc information area 10. However, alaser element used by the disc manufacturer for obtaining therecommended values is different from a laser element incorporated in anoptical disc drive apparatus, in respect to laser characteristics, suchas the wavelength, the rising time of the laser power, and the like.Further, even a laser element of the same optical disc drive, the lasercharacteristics thereof vary because of a variation of the ambienttemperature or deterioration which occurs over time. Thus, in an actualcase, test recording is performed on the OPC area 11 while increasinglyand decreasingly changing the laser parameters stored in the discinformation area 10 so as to obtain an optimum recording power.

A defect management area 12 and a spare areas 13 are provided for defectmanagement, i.e., provided for replacing a sector of the user data area8 in which recording/reproduction cannot be appropriately performed(referred to as a “defective sector”) with another well-conditioned(i.e., sufficiently usable) sector. In a rewritable single-layer opticaldisc, such as a 650 MB phase-change optical disc (called a PD) definedin the ECMA-240 format, or the like, defect management is generallyperformed.

The spare area 13 includes a sector for replacing a defective sector(referred to as a spare sector). A sector which is already employed inplace of a defective sector is referred to as a replacement sector. In aDVD-RAM, spare areas 13 are placed at two positions, one at the innerperiphery and the other at the outer periphery of the user data area 8.In the above-described PD, spare areas 13 are provided at 10 positions,and their arrangement varies depending on the medium. In the example ofFIG. 5, for the sake of simplicity, a spare area 13 is provided at onlyone portion at the outer periphery of the user data area 8.

The defect management area 12 includes: a disc definition structure(DDS) storing area 20 storing a format designed for defect management,which includes the size of the spare area 13 and the position where thespare area 13 is placed; a defect management sector (DMS) storing area21 storing data for managing the defect of the defect management area 12itself; a defect list (DL) storing area 22 storing a list of defectscontaining the positions of defective sectors and the positions ofreplacement sectors; and a spare defective list (spare DL) storing area23 which is used to replace the defect list (DL) storing area 22 when itis not usable. In view of robustness, many discs are designed based on aspecification such that each of the inner perimeter portion and outerperimeter portion of a disc has one defect management area 12, and eachdefect management area 12 duplicately stores the same contents, i.e.,the defect management areas 12 of the disc have the four copies of thesame contents in total.

FIG. 5B shows data stored in a DMS 21. The data stored in the DMS 21 arethe number of DL sectors 30 which indicates the number of sectorsstoring a defect list, and a list of DL sector addresses 31 each ofwhich indicates the address of a sector. For the sake of simplicity, DLstoring areas 22 each are herein assumed to include only one sector. Ifit is determined that a DL storing area 22 is defective when updating adefect list because of detection of a new defective sector, thefollowing spare DL storing area 23 is used to record the defect list. Inthis case, the DL sector address list 31 is updated so as to indicatethe sector address of the spare DL storing 23.

FIG. 5C shows data stored in a DL storing area 22. The data stored inthe DL storing area 22 area DL identifier 32 which is a uniqueidentifier for identifying a defect list, and the number of defectivesectors 33 registered on the defect list. The DL storing area 22 furtherincludes a plurality of defect entry areas 34 each including the addressof a defective sector and the address of a replacement sector. It is nowassumed that there are n defects registered (n is an integer greaterthan or equal to 3). In this case, the number of defective sectors 33indicates n.

A first defect entry area 34 stores a replacement status 40, a defectivesector address 41, and a replacement sector address 42. In other words,a single defect entry area stores information relating to a process forreplacing a single defective sector. The replacement status 40 is a flagindicating whether or not replacement is applied to a defective sector.When replacement is performed, a value 0 is set in the replacementstatus 40. When replacement is not applied, a value 1 is set in thereplacement status 40. When the value 1 is set in the replacement status40, an optical disc drive apparatus accesses a defective sector. In thiscase, even if an error occurs in a read out process, the error isignored and the read out process is continued while data contains theerror. Such a process may be applied for recording and reproduction ofvideo and audio data requiring continuous recording or reproduction.This is because interruptions in reproduction of video or audio due toreplacement of a defective area with a distant spare area appears moresignificant than disturbances in video or audio due to the erroneousdata itself. The defective sector address 41 contains the address of asector which is determined to be defective. The replacement sectoraddress 42 contains the address of a sector in a spare area 13, whichsector replaces a defective sector indicated by the defective sectoraddress 41. The n defect entry areas are arranged in ascending order ofthe address of a defective sector.

As described above, defect management is essential for rewritableoptical discs to obtain substantially the same data reliability as thatof read-only optical discs.

Although there are read-only optical discs having a plurality ofrecording layers, all existing rewritable optical discs have only asingle recording layer. The above-described defect management for arewritable optical disc is directed to management of only one recordinglayer.

If defect management as described above was simply applied to an opticaldisc having a plurality of recording layers, a defect management areawould be provided for each recording layer. A defect management isseparately performed for each recording layer. A typicalrecording/reproduction apparatus for rewritable optical discs transfersa defect list into a memory within the apparatus when the apparatus isactuated (initial process). This is because defect managementinformation can be accessed at high speed, which is constantlyreferenced in recording and reproduction of user data. Therefore, when arecording/reproduction apparatus handles an optical disc having aplurality of recording layers, the apparatus needs to read all defectmanagement areas in all recording layers when loading a disk into theapparatus. This poses a problem such that it takes a long time beforestarting actual recording or reproduction of a disc. Moreover, defectmanagement is separately performed for each recording layer, andtherefore, if a finite defect list storing area is exhausted in acertain recording layer, any defect list storing areas of otherrecording layers are not available for that exhausted recording layer.This poses a problem such that defect list storing areas cannot beefficiently used.

As used herein, the term “initial process” for an optical disc refers toa process in which defect management information or the like is read outbefore recording or reproduction user data or the like on the disc whena recording/reproduction apparatus is actuated.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a multi-layeredinformation recording medium comprises: a plurality of recording layers:a user data area for recording user data, provided in at least two ofthe plurality of recording layers; and a defect list storing area forstoring a defect list, wherein when at least one defective area isdetected in the user data area, the defect list is used to manage the atleast one defective area.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise a defect list location informationstoring area for storing defect list location information indicating thelocation of the defect list storing area. The defect list locationinformation storing area may be provided in one of the plurality ofrecording layers which is predetermined as a reference layer.

In one embodiment of this invention, the reference layer may be one ofthe plurality of recording layers which is located at a predetermineddistance from the data read-out surface of the multi-layered informationrecording medium.

In one embodiment of this invention, the reference layer may be one ofthe plurality of recording layers which is located at the shortestdistance from the data read-out surface of the multi-layered informationrecording medium.

In one embodiment of this invention, the reference layer may be one ofthe plurality of recording layers which is located at the longestdistance from the data read-out surface of the multi-layered informationrecording medium.

In one embodiment of this invention, the defect list may indicate thelocation of the detected at least one defective area by a layer numberfor distinguishing the plurality of recording layer from each other andan intralayer address for indicating a position in each of the pluralityof recording layers.

In one embodiment of this invention, the defect list storing area may beprovided in one of the plurality of recording layer, and the defect listlocation information may indicate the location of the defect liststoring area by a layer number for distinguishing the plurality ofrecording layer from each other and an intralayer address for indicatinga position in each of the plurality of recording layers.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise a spare area containing at leastone replacement area. When at least one defective area is detected inthe user data area, the at least one replacement area may be used inplace of the at least one defective area.

In one embodiment of this invention, when the defective area is replacedwith the replacement area, the defect list may indicate the location ofthe defective area and the location of the replacement area byrespective layer numbers for distinguishing the plurality of recordinglayers from each other and respective intralayer addresses forindicating a position in each of the plurality of recording layers.

In one embodiment of this invention, the defect list storing area may beprovided one of the plurality of recording layers. The multi-layeredinformation recording medium may further comprise an additional defectlist storing area for storing a defect list having the same contents asthe contents of the defect list stored in the defect list storing area.The additional defect list storing area may be provided in another oneof the plurality of recording layers.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise a first defect list locationinformation storing area for storing first defect list locationinformation indicating the location of the defect list storing area, anda second defect list location information storing area for storing asecond defect list location information indicating the location of theadditional defect list storing area. The first defect list locationinformation storing area may be provided in the same recording layer asthat in which the defect list storing area is provided, and the seconddefect list location information storing area may be provided in thesame recording layer as that in which the additional defect list storingarea is provided.

In one embodiment of this invention, the recording layer in which thedefect list storing area is provided may comprise a first defectmanagement area containing the defect list storing area and the firstdefect list location information storing area. The recording layer inwhich the additional defect list storing area may be provided comprisesa second defect management area containing the additional defect liststoring area and the second defect list location information storingarea. Logical addresses may be assigned to the user data area. An areaof the user data area to which the smallest logical address is assignedis provided in the recording layer in which the defect list storing areamay be provided. An area of the user data area to which the greatestlogical address is assigned may be provided in the recording layer inwhich the additional defect list storing area is provided. The firstdefect management area may be adjacent to the area to which the smallestlogical address is assigned. The second defect management area may beadjacent to the area to which the greatest logical address is assigned.

According to another aspect of the present invention, a multi-layeredinformation recording medium comprises: a plurality of recording layers;a user data area for recording user data, provided in at least two ofthe plurality of recording layers; a defect management area provided inat least one of the plurality of recording layers; and a spare defectlist storing area provided in another one of the plurality of recordinglayers. The defect management area contains a plurality of first defectlist storing areas for storing a defect list, wherein when at least onedefective area is detected in the user data area, the defect list isused to manage the at least one defective area. The spare defect liststoring area contains a plurality of second defect list storing areascapable of being used in place of the plurality of first defect liststoring areas when none of the plurality of first defect list storingareas is usable.

In one embodiment of this invention, the defect management area and thespare defect list storing area may be located at substantially the sameradial positions in the multi-layered information recording medium.

In one embodiment of this invention, the defect management area mayfurther comprise a defect list location information storing area forstoring defect list location information indicating the location of anarea storing the defect list among the plurality of first defect liststoring areas and the plurality of second spare defect list storingareas.

According to another aspect of the present invention, an apparatus forreproducing information recorded in a multi-layered informationrecording medium is provided. The multi-layered information recordingmedium comprises: a plurality of recording layers; a user data area forrecording user data, provided in at least two of the plurality ofrecording layers; and a defect list storing area for storing a defectlist, wherein when at least one defective area is detected in the userdata area, the defect list is used to manage the at least one defectivearea. The apparatus comprises: an optical head section capable ofoptically reading the information recorded in the multi-layeredinformation recording medium from one side of the multi-layeredinformation recording medium; and a control section for controllingdefect management using the optical head section. The defect managementcomprises the steps of: reproducing the defect list stored in the defectlist storing area; and reproducing the user data recorded in the userdata area based on the reproduced defect list.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise: a defect list locationinformation storing area for storing defect list location informationindicating the location of the defect list storing area, wherein thedefect list location information storing area is provided in one of theplurality of recording layers which is predetermined as a referencelayer, the defect management further comprises identifying the locationof the defect list storing area by reproducing the defect list locationinformation stored in the defect list location information storing area.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise: a spare area for containing atleast one replacement area, wherein when at least one defective area isdetected in the user data area, the at least one replacement area may beused in place of the at least one defective area. The defect list mayindicate that a defective area present in the user data area is replacedwith the replacement area contained in the spare area. The step ofreproducing the user data may comprise reproducing user data from thereplacement area indicated by the defect list instead of the defectivearea indicated by the defect list.

According to another aspect of the present invention, an apparatus forrecording information in a multi-layered information recording medium isprovided. The multi-layered information recording medium comprises: aplurality of recording layers; a user data area for recording user data,provided in at least two of the plurality of recording layers; and adefect list storing area for storing a defect list, wherein when atleast one defective area is detected in the user data area, the defectlist is used to manage the at least one defective area. The apparatuscomprises: an optical head section capable of optically recording theinformation in the multi-layered information recording medium from oneside of the multi-layered information recording medium; and a controlsection for controlling defect management using the optical headsection. The defect management comprises the steps of: determiningwhether or not a defective area is present in the user data area duringrecording of user data in the user data area; and updating the defectlist so as to manage a defective area when it is determined that thedefective area is present in the user data area.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise an additional defect list storingarea capable of being used in place of the defect list storing area whenthe defect list storing area is unusable. The defect management mayfurther comprise recording a defect list having the same contents as thecontents of a defect list stored in the defect list storing area to theadditional defect list storing area, when the defect list storing areais unusable.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise: a defect list locationinformation storing area for storing defect list location informationindicating the location of a defect list. The defect list locationinformation storing area may be provided in one of the plurality ofrecording layers which is predetermined as a reference layer. The defectmanagement may further comprise updating the defect list locationinformation so that the defect list location information indicates theadditional defect list storing area, when the additional defect liststoring area is used in place of the defect list storing area.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise: a defect management area providedin one of the plurality of recording layers; and a spare defect liststoring area provided in another one of the plurality of recordinglayer. The defect management area may comprise a plurality of defectlist storing areas, the spare defect list storing area comprises aplurality of additional defect list storing areas, the defect liststoring area is one of the plurality of defect list storing areas, theadditional defect list storing area is one of the plurality ofadditional defect list storing area, and when none of the plurality ofdefect list storing areas is usable, the additional defect list storingarea is used in place of the defect list storing area.

In one embodiment of this invention, the defect list storing area may beprovided in one of the plurality of recording layers, and the additionaldefect list storing area may be provided in the same recording layer asthat in which the defect list storing area is provided.

In one embodiment of this invention, the defect list storing area may beprovided in one of the plurality of recording layers, and the additionaldefect list storing area may be provided in another one of the pluralityof recording layers.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise: a spare area for containing atleast one replacement area, wherein when at least one defective area isdetected in the user data area, the at least one replacement area may beused in place of the at least one defective area. The defect managementmay further comprise replacing the defective area present in the userdata area with the replacement area contained in the spare area.

According to another aspect of the present invention, a method forreproducing information recorded in a multi-layered informationrecording medium is provided. The multi-layered information recordingmedium comprises: a plurality of recording layers; a user data area forrecording user data, provided in at least two of the plurality ofrecording layers; and a defect list storing area for storing a defectlist, wherein when at least one defective area is detected in the userdata area, the defect list is used to manage the at least one defectivearea. The method comprises the steps of: reproducing the defect liststored in the defect list storing area; and reproducing the user datarecorded in the user data area based on the reproduced defect list.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise: a defect list locationinformation storing area for storing defect list location informationindicating the location of the defect list storing area. The defect listlocation information storing area may be provided in one of theplurality of recording layers which is predetermined as a referencelayer. The method may further comprise identifying the location of thedefect list storing area by reproducing the defect list locationinformation stored in the defect list location information storing area.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise: a spare area for containing atleast one replacement area, wherein when at least one defective area isdetected in the user data area, the at least one replacement area may beused in place of the at least one defective area. The defect list mayindicate that a defective area present in the user data area is replacedwith the replacement area contained in the spare area. The step ofreproducing the user data may comprise reproducing user data from thereplacement area indicated by the defect list instead of the defectivearea indicated by the defect list.

According to another aspect of the present invention, a method forrecording information in a multi-layered information recording medium isprovided. The multi-layered information recording medium may comprise: aplurality of recording layers; a user data area for recording user data,provided in at least two of the plurality of recording layers; and adefect list storing area for storing a defect list, wherein when atleast one defective area is detected in the user data area, the defectlist is used to manage the at least one defective area. The methodcomprises the steps of: determining whether or not a defective area ispresent in the user data area during recording of user data in the userdata area; and updating the defect list so as to manage a defective areawhen it is determined that the defective area is present in the userdata area.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise an additional defect list storingarea capable of being used in place of the defect list storing area whenthe defect list storing area is unusable. The method may furthercomprise recording a defect list having the same contents as thecontents of a defect list stored in the defect list storing area to theadditional defect list storing area, when the defect list storing areais unusable.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise: a defect list locationinformation storing area for storing defect list location informationindicating the location of a defect list. The defect list locationinformation storing area may be provided in one of the plurality ofrecording layers which is predetermined as a reference layer. The methodmay further comprise updating the defect list location information sothat the defect list location information indicates the additionaldefect list storing area, when the additional defect list storing areais used in place of the defect list storing area.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise: a defect management area providedin one of the plurality of recording layers; and a spare defect liststoring area provided in another one of the plurality of recordinglayer. The defect management area may comprise a plurality of defectlist storing areas. The spare defect list storing area may comprise aplurality of additional defect list storing areas. The defect liststoring area may be one of the plurality of defect list storing areas.The additional defect list storing area is one of the plurality ofadditional defect list storing area. When none of the plurality ofdefect list storing areas is usable, the additional defect list storingarea may be used in place of the defect list storing area.

In one embodiment of this invention, the defect list storing area may beprovided in one of the plurality of recording layers, and the additionaldefect list storing area may be provided in the same recording layer asthat in which the defect list storing area is provided.

In one embodiment of this invention, the defect list storing area may beprovided in one of the plurality of recording layers, and the additionaldefect list storing area may be provided in another one of the pluralityof recording layers.

In one embodiment of this invention, the multi-layered informationrecording medium may further comprise: a spare area for containing atleast one replacement area, wherein when at least one defective area isdetected in the user data area, the at least one replacement area may beused in place of the at least one defective area. The method may furthercomprise replacing the defective area present in the user data area withthe replacement area contained in the spare area.

Thus, the invention described herein makes possible the advantages ofproviding a defect management method capable of shortening the timerequired to read a defect management area in an initial process for adisc and efficiently managing defective areas.

These and other advantages of the present invention will become apparentto those skilled in the art upon reading and understanding the followingdetailed description with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a track and sectors in an optical disc.

FIG. 2 is a diagram showing a principle of reproduction of an opticaldisc comprising two recording layers.

FIG. 3A is a diagram showing a groove pattern of a second recordinglayer in a parallel path DVD.

FIG. 3B is a diagram showing a groove pattern of a first recording layerin a parallel path DVD.

FIG. 3C is a diagram showing a reproduction direction of a parallel pathDVD.

FIG. 3D is a diagram showing assignment of sector numbers in a parallelpath DVD.

FIG. 4A is a diagram showing a groove pattern of a second recordinglayer in an opposite path DVD.

FIG. 4B is a diagram showing a groove pattern of a first recording layerin an opposite path DVD.

FIG. 4C is a diagram showing a reproduction direction of an oppositepath DVD.

FIG. 4D is a diagram showing assignment of sector numbers in an oppositepath DVD.

FIG. 5A is a diagram showing locations of areas in a DVD-RAM.

FIG. 5B is a diagram showing a data structure of a DMS shown in FIG. 5A.

FIG. 5C is a diagram showing a data structure of a DL shown in FIG. 5A.

FIG. 6 is a diagram showing locations of areas in a multi-layeredinformation recording medium according to Embodiment 1 of the presentinvention.

FIG. 7 is a diagram showing a data structure of a first defectmanagement area in Embodiment 1 of the present invention.

FIG. 8 is a diagram showing a data structure of a first spare DL storingarea in Embodiment 1 of the present invention.

FIG. 9 is a diagram showing the relationship between a first spare DLstoring area and a DDS area in Embodiment 1 of the present invention.

FIG. 10A is a diagram showing locations of a first defect managementarea and a first spare DL storing area in Embodiment 1 of the presentinvention.

FIG. 10B is a diagram showing locations of a first defect managementarea and a first spare DL storing area in Embodiment 1 of the presentinvention.

FIG. 10C is a diagram showing locations of a first defect managementarea and a first spare DL storing area in Embodiment 1 of the presentinvention.

FIG. 11 is a diagram showing locations of areas in a multi-layeredinformation recording medium according to Embodiment 2 of the presentinvention.

FIG. 12 is a diagram showing a data structure of a first defectmanagement area in Embodiment 2 of the present invention.

FIG. 13 is a diagram showing a recording/reproduction apparatusaccording to Embodiment 3 of the present invention.

FIG. 14 is a flowchart for illustrating a procedure of obtaining defectmanagement information in Embodiment 3 of the present invention.

FIG. 15 is a flowchart for illustrating a reproduction procedure ofsectors according to Embodiment 3 of the present invention, whereinreplacement is considered.

FIG. 16 is a flowchart for illustrating conversion of LSN to PSN inEmbodiment 3 of the present invention.

FIG. 17 is a flowchart for illustrating a procedure of updating defectmanagement information in Embodiment 3 of the present invention.

FIG. 18 is a flowchart for illustrating a recording procedure accordingto Embodiment 3 of the present invention, wherein replacement isconsidered.

FIG. 19 is a diagram showing locations of areas in a multi-layeredinformation recording medium according to Embodiment 4 of the presentinvention.

FIG. 20 is a diagram showing a data structure of a first defectmanagement area in a multi-layered information recording mediumaccording to Embodiment 4 of the present invention.

FIG. 21 is a diagram showing locations of areas in a multi-layeredinformation recording medium according to Embodiment 5 of the presentinvention.

FIG. 22 is a diagram showing locations of areas in a multi-layeredinformation recording medium according to Embodiment 6 of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1

Hereinafter, a multi-layered information recording medium according toEmbodiment 1 of the present invention will be described with referenceto the accompanying drawings. A multi-layered information recordingmedium as used herein refers to an information recording mediumcomprising at least two recording layers.

FIG. 6 is a diagram showing a multi-layered information recording medium600 according to Embodiment 1 of the present invention. Themulti-layered information recording medium 600 comprises two recordinglayers 51 and 52. The multi-layered information recording medium 600contains a user data area 602 for recording user data. The user dataarea 602 straddles a boundary between the two recording layers 51 and52. In Embodiment 1 of the present invention, the upper recording layer(51) shown in FIG. 6 is referred to as a first recording layer, and thelower recording layer (52) is referred to as a second recording layer.

The first recording layer 51 is located at a predetermined distance froma surface of the multi-layered information recording medium 600 throughwhich data is read out (data read-out surface). The first recordinglayer 51 is referred to as a reference layer. This predetermineddistance is equal to a distance from the data read-out surface of anoptical disc comprising only one recording layer to the recording layer.A reference layer is predetermined among a plurality of recordinglayers.

The first recording layer 51 contains, from the inner periphery to theouter periphery along the recording/reproduction direction of themulti-layered information recording medium 600, a lead-in area 601, afirst user data area 15 which is a portion of the user data area 602,and a middle area 603. The second recording layer 52 contains, from theouter periphery to the inner periphery along the recording/reproductiondirection of the multi-layered information recording medium 600, amiddle area 603, a second user data area 16 which is a portion of theuser data area 602, and a lead-out area 604.

The lead-in area 601 provided in the first recording layer 51 (referencelayer) contains a control data area 610 for storing control informationfor the multi-layered information recording medium 600, and a firstdefect management area 611 (DMA1) and a second defect management area612 (DMA2) for recording defect management information relating to adefective area (defect management information contains disc definitionstructure data, a defect list, and the like). The middle area 603 of thefirst recording layer 51 contains a third defect management area 613(DMA3) and a fourth defect management area 614 (DMA4). The first defectmanagement area 611, the second defect management area 612, the thirddefect management area 613, and the fourth defect management area 614each store the same defect management information. This is because byduplicately recording the same defect management information in aplurality of areas on the inner periphery and outer periphery of themulti-layered information recording medium 600, the reliability of thedefect management information is improved. A defective area is herein adefective sector.

The middle area 603 of the second recording layer 52 contains a thirdspare defect list (DL) area 622 (spare DL3) and a fourth spare DLstoring area 623 (spare DL4) for storing spare a defect list. The thirdspare DL storing area 622 (spare DL3) may be used in place of the thirddefect management area 613 (DMA3) of the first recording layer 51 whenDMA3 is no longer appropriately recordable (unusable) due to degradationor the like. The fourth spare DL storing area 623 (spare DL4) may beused in place of the fourth defect management area 613 (DMA4) of thefirst recording layer 51 when DMA4 is no longer appropriately recordable(unusable) due to degradation or the like. The lead-out area 604contains a first spare DL storing area 620 (spare DL1) and a secondspare DL storing area 621 (spare DL2) for storing a spare defect list.The first spare DL storing area 620 (spare DL1) may be used in place ofthe first defect management area 611 (DMA1) of the first recording layer51 when DMA1 is no longer appropriately recordable (unusable) due todegradation or the like. The second spare DL storing area 621 (spareDL2) may be used in place of the second defect management area 612(DMA2) of the first recording layer 51 when DMA2 is no longerappropriately recordable (unusable) due to degradation or the like.

It is now assumed that as shown in FIG. 6, a defective area A 630 ispresent in the first user data area 15, and a defective area B 631 ispresent in the second user data area 16. Although the optical disccomprising the spare area 13 is described in the DESCRIPTION OF THERELATED ART Section (FIG. 5A), the multi-layered information recordingmedium 600 of Embodiment 1 does not contain such a spare area.Therefore, none of the defective area A 630 and the defective area B 631is replaced with a spare area.

Referring to FIG. 7, a data structure of the first defect managementarea 611 (DMA1) will be described below. Note that the first defectmanagement area 611 (DMA1), the second defect management area 612(DMA2), the third defect management area 613 (DMA3), and the fourthdefect management area 614 (DMA4) each store the same defect managementinformation. Here, the first defect management area 611 (DMA1) will bedescribed.

The first defect management area 611 (DMA1) of the first recording layer51 (reference layer) contains a disc definition structure (DDS) area 700(DDS) and a plurality of defect list (DL) storing areas. In Embodiment1, the first defect management area 611 (DMA1) contains a first DLstoring area 701, a second DL storing area 702, a third DL storing area703, and a fourth DL storing area 704. Not all of these DL storing areasare simultaneously used. Any one of the DL storing areas is used. In theexample shown in FIG. 7, the first DL storing area 701 is a defectivearea, and the second DL storing area 702 is used. The third DL storingarea 703 and the fourth DL storing area 704 are unused. The second DLstoring area 702 stores a defect list (DL) 709. When at least onedefective area is detected in the use data area 602, the defect list 709is used to manage the detected defective area. The defect list 709contains the defective area(s) detected in the user data area 602 andthe location information of their replacement area(s). The DDS area 700functions as a defect list location information storing area for storingdefect list location information indicating the location of a DL storingarea storing the defect list 709 (e.g., the second DL storing area 702in FIG. 7). The DDS area 700 also stores information indicating a defectverification status or the like. If the second DL storing area 702becomes defective due to repetition of write operations or the like, thethird DL storing area 703 is used.

The DDS area 700 contains a DDS identifier 710 for identifying a DDS, aDL start sector layer number 711 indicating a recording layer containinga DL storing area currently used among a plurality of recording layers(a layer number may be any information which permits to distinguish aplurality of recording layers from each other), a DL start sector number712 indicating the location of a DL storing area currently used in arecording layer using a sector number which is uniquely identifiable inthe recording layer, and a spare area size area 713 for storinginformation relating to the size of a spare area. The DL start sectorlayer number 711 and the DL start sector number area 712 contain defectlist location information. Since the multi-layered information recordingmedium 600 does not contain a spare area, a value 0 is set in the sparearea size area 713. The spare area size area 713 can contain the numberof recording layers, or a plurality of sizes depending on the locationof a spare area. For the sake of simplicity, it is here assumed thatwhen the multi-layered information recording medium 600 is provided withspare areas, a spare area having a size specified by the spare area sizearea 713 is provided in both the inner periphery and the outer peripheryof each recording layer.

The defect list 709 contains a DL header 720 and two pieces of defectentry data. The DL header area 720 contains a DL identifier 731 foridentifying a defect list, a DL update count 732 for indicating thenumber of repetitions of rewriting the defect list, and a number of DLentries 733 for indicating the number of defect entries stored in areasfollowing the DL header 720. In the example shown in FIG. 7, two piecesof defect entry data, i.e., a defect entry A 721 and a defect entry B722, are registered, and therefore, the number of DL entries 733indicates two.

The defect entry A 721 contains a replacement status flag 734, adefective sector layer number 735, a defective sector number 736, areplacement sector layer number 737, and a replacement sector number738. Similarly, the defect entry B 722 contains a replacement statusflag 739, a defective sector layer number 740, a defective sector number741, a replacement sector layer number 742, and a replacement sectornumber 743. The data contained in the defect entry A 721 will bedescribed. The replacement status flag 734 is a flag indicating whetheror not a defective area is replaced with a spare area (normal area) andindicates a value 1 when no replacement is performed. In Embodiment 1,no spare area is allocated in the multi-layered information recordingmedium 600, and therefore, a value 1 indicating no replacement is set inthe replacement status flag 734.

The defective sector layer number 735 indicates the layer number of arecording layer in which a defective area is detected. The replacementsector layer number 737 indicates the layer number of a recording layerin which a replacement area is provided. These layer numbers are anyinformation which permits to distinguish a plurality of recording layersfrom each other. The defect entry A 721 is used to manage the defectivearea A 630 (FIG. 6). The defect entry B 722 is used to manage thedefective area B 631 (FIG. 6). In this case, for example, a value 1indicating the first recording layer 51 is set in the defective sectorlayer number 735, while a value 2 indicating the second recording layer52 is set in the defective sector layer number 740. The defective sectornumber 736 indicates an identification value from which the location ofa defective area is uniquely determined in the recording layer in whichthe defective area is detected. The sector number is a value whichincrements by ones from the inner periphery toward the outer peripheryof the multi-layered information recording medium 600, for example.

Even if the sector number of any sector in the first recording layer 51is the two's complement of the sector number of a corresponding sectorin the second recording layer 52 where the sectors are placed at thesame radial position, the above-described conditions are satisfied as inthe opposite paths of a DVD-ROM. For example, consider that physicalsector numbers (PSNs) are represented in the 28-bit format, and the PSNsof the first recording layer 51 are within the range of 0000000h to0FFFFFFh (“h” means that the value is represented by a hexadecimalnumber). When the PSN of a certain sector in the first recording layer51 is 0123450h, the PSN of a corresponding sector in the secondrecording layer 52 at the same radial position is FEDCBAFh. In thiscase, the most significant bit of the PSN for the first layer isconstantly 0 and the most significant bit of the PSN for the secondlayer is constantly F. Thus, the most significant bit can be used toindicate the layer number.

Similarly, a value capable of uniquely identifying the location of anarea replacing a defective area is set in each of the replacement sectorlayer number 737 and the replacement sector number 738. Note that inEmbodiment 1, since there is no spare area, no replacement is performed.Therefore, 0 is set in each of the replacement sector layer numbers 737and 742, while 00000000h is set in each of the replacement sectornumbers 738 and 743.

If a defect management area (DMA) was separately provided in each of thefirst recording layer 51 and the second recording layer 52, it isnecessary for the recording/reproduction apparatus to read out defectmanagement information from each recording layer as described above.However, as described above, the multi-layered information recordingmedium 600 according to Embodiment 1 of the present invention can obtaindefect management information for all of the recording layers only byreading the defect management information from the reference layer.Therefore, it is possible to perform an initial process for themulti-layered information recording medium 600 simply and in a shorttime.

In the multi-layered information recording medium 600, the defectiveareas of all of the recording layers are managed in a unified manner.Therefore, DL storing areas can be used more efficiently than whendefective areas are managed for each recording layer. For example, anoptical disc is assumed to comprise two recording layers containing amaximum total of 1000 sectors for which occurrence of a defective areais managed. In this case, when defect management information isseparately stored in each recording layer, it is necessary to provideeach layer with a DL storing area which can contain defect entries of amaximum of 1000 sectors. This is because it is necessary to handle anunbalanced situation such that 950 defective sectors are present in thefirst recording layer 51 while no defective area is present in thesecond recording layer 52. On the other hand, in the case of themulti-layered information recording medium 600 according to Embodiment 1of the present invention, defective areas in all of the recording layersare managed in an unified manner using a DL storing area which cancontain defect entries of a maximum of 1000 sectors, and therefore, thetotal size of all DL storing areas can be reduced.

Next, the first spare DL storing area 620 (spare DL1) included in thesecond recording layer 52 will be described with reference to FIG. 8.The first spare DL storing area 620 (spare DL1) contains a plurality ofDL storing areas. In the multi-layered information recording medium 600according to Embodiment 1 of the present invention, the first spare DLstoring area 620 (spare DL1) contains four DL storing areas, i.e., afifth DL storing area 705, a sixth DL storing area 706, a seventh DLstoring area 707, and an eighth DL storing area 708, each of which isunused. A DL storing area contained in the first spare DL storing area620 (spare DL1) is used in place of the DL storing areas contained inthe first defect management area 611 (DMA1) when all of them aredetermined to be defective and unusable. A defect list having the samecontents as those of a defect list stored in a DL storing area containedin the first defect management area 611 (DMA1) is stored in a DL storingarea contained in the first spare DL storing area 620 (spare DL1).

As does the first spare DL storing area 620 (spare DL1), the secondspare DL storing area 621 (spare DL2), the third spare DL storing area622 (spare DL3), and the fourth spare DL storing area 623 (spare DL4)each contain a plurality of DL storing areas. A DL storing areacontained in the second spare DL storing area 621 (spare DL2) is used inplace of the DL storing areas contained in the second defect managementarea 612 (DMA2) when all of them are determined to be defective andunusable. A DL storing area contained in the third spare DL storing area622 (spare DL3) is used in place of the DL storing areas contained inthe third defect management area 613 (DMA3) when all of them aredetermined to be defective and unusable. A DL storing area contained inthe fourth spare DL storing area 623 (spare DL4) is used in place of theDL storing areas contained in the fourth defect management area 614(DMA4) when all of them are determined to be defective and unusable.

In the above-described case, when the first defect management area 611(DMA1) is unusable, the first spare DL storing area 620 (spare DL1) isused. Alternatively, for example, another spare DL storing area, such asthe second spare DL storing area 621 or the like, may be used.

FIG. 9 shows an example of use of the first spare DL storing area 620(spare DL1) in the second recording layer 52. In the example of FIG. 9,four DL storing areas in the first defect management area 611 (DMA1) aredetermined to be defective. In this case, a defect list is recorded in aDL storing area of the first spare DL storing area 620 (spare DL1)contained in the second recording layer 52. As shown in FIG. 9, when thefifth DL storing area 705 is also defective, the defect list 709 (FIG.7) is recorded in the sixth DL storing area 706. In this case, a value 2which indicates the use of a DL storing area contained in the secondrecording layer 52, is set in the DL start sector layer number 711 ofthe DDS area 700. The sector number of the starting position of thesixth DL storing area 706 is stored in the DL start sector number 712.

As described above, in the multi-layered information recording medium600 according to Embodiment 1 of the present invention, the recordinglayer other than the reference layer contains a spare DL storing area.Therefore, even if a DL storing area in the reference layer becomesunusable, the spare DL storing area can be used to keep the reliabilityof defect management information. Particularly, this technique is usefulfor improvement of reliability of recording media which are likely to bedegraded due to repetition of write operations. Note that in Embodiment1 the fifth DL storing area 705, the sixth DL storing area 706, theseventh DL storing area 707, and the eighth DL storing area 708 are usedin this order, however, these areas may be used in descending order fromthe eighth DL storing area 708 when data is recorded in the secondrecording layer 52 from the outer periphery to the inner periphery ofthe multi-layered information recording medium 600.

Next, with reference to FIGS. 10A and 10B, a description will be givenof the relationship between the radial position of a defect managementarea in the first recording layer 51 (reference layer) and the radialposition of a spare DL storing area in the second recording layer 52.FIG. 10A is an enlarged diagram showing locations of the lead-in area601, the middle area 603, and the lead-out area 604 in the multi-layeredinformation recording medium 600 according to Embodiment 1 of thepresent invention. It is now assumed that the first spare DL storingarea 620 (spare DL1) is used. In this case, a defect list is stored inthe first spare DL storing area 620 (spare DL1), which is indicated bythe DL start sector number 712 of the DDS area 700. The first spare DLstoring area 620 (spare DL1) and the first defect management area 611(DMA1) are desirably located at substantially the same radial positions.If so, a recording/reproduction head needs to be shifted by only a smalldistance in a radial direction. Thus, as shown in FIG. 10A, the first DLstoring area 701 in the first defect management area 611 (DMA1) and thefifth DL storing area 705 in the first spare DL storing area 620 (spareDL1) are desirably located at substantially the same radial positions.This is because when the contents of the first defect management area611 (DMA1) are read out in an initial process for the multi-layeredinformation recording medium 600 and it is determined according to theDDS area 700 that a defect list is stored in the fifth DL storing area705 of the first spare DL storing area 620 (spare DL1), havingsubstantially the same radial position makes it possible to access thearea quickly. However, an error or the like may occur when the firstrecording layer 51 and the second recording layer 52 are attachedtogether in a fabrication step, thereby making it difficult to arrangethe first spare DL storing area 620 (spare DL1) and the first defectmanagement area 611 (DMA1) at the same radial position. As a result, asshown in FIG. 10B, the first recording layer 51 is slightly shifted fromthe second recording layer 52. In FIG. 10B, the first defect managementarea 611 (DMA1) in the first recording layer 51 is radially shifted fromthe first spare DL storing area 620 (spare DL1) in the second recordinglayer 52. The magnitude of the shift is called an attachment error in adisc fabrication process.

Considering the operation of a recording/reproduction apparatus forrecording and reproduction of the multi-layered information recordingmedium 600, an error occurs due to the inaccuracy of control of lenspositions, the eccentricity of a disc, or the like when a focal point isswitched between the first recording layer 51 and the second recordinglayer 52. Therefore, an error in radial position between the firstrecording layer 51 and the second recording layer 52 may be tolerablewithin a predetermined range based on the attachment precision ofrecording layers in a disc fabrication process as shown in FIG. 10B.

Further, for the positional relationship between a defect managementarea and a spare DL storing area, a smaller distance between a DDS areain a defect management area and a DL storing area in a correspondingspare DL storing area is preferable in view of an access time. Forexample, as shown in FIG. 10C compared to FIG. 10A, each DL storing areain a spare DL storing area may be shifted toward the inner periphery bya used area in a spare DL storing area.

As described above, when defect management areas (DMAm [m=1, 2, 3, 4])in a reference layer and spare DL storing area (spare DLm) in arecording layer(s) other than the reference layer are located atsubstantially the same radial positions, it is possible to access adefect list in a short time even if the defect list is stored in a spareDL storing area (spare DLm).

The multi-layered information recording medium 600 according toEmbodiment 1 of the present invention has been heretofore described.

As described above, in the multi-layered information recording medium600 according to Embodiment 1 of the present invention comprising aplurality of recording layers, defect management information relating toall of the recording layers is stored in a single recording layer.Therefore, it is possible to read out the defect management informationmore simply and rapidly.

In the multi-layered information recording medium 600 according toEmbodiment 1 of the present invention, all defect management informationrelating to a plurality of recording layers is stored in a referencelayer. Therefore, even if a larger number of defective areas areintensively present in one recording layer, it is possible to use adefect entry area efficiently.

In the multi-layered information recording medium 600 according toEmbodiment 1 of the present invention, a spare DL storing area isprovided in a recording layer other than a reference layer. Therefore,it is possible to significantly improve the reliability of defectmanagement information of defects due to degradation of medium material.

In the multi-layered information recording medium 600 according toEmbodiment 1 of the present invention, a spare DL storing area is placedwithin a predetermined error range from the radial position of a defectmanagement area in a reference layer. Therefore, it is possible toreduce an access time required to read a spare DL storing area afterreading a DDS area.

Note that Embodiment 1 shows an opposite path disc in which recordingand reproduction are performed from the inner periphery to the outerperiphery of the first recording layer 51 and from the outer peripheryto the inner periphery of the second recording layer 52, though aparallel path disc can be similarly managed in which recording andreproduction are performed from the inner periphery to the outerperiphery in all recording layers. The arrangement of recording layersis not particularly limited as long as a defect management area and aspare DL storing area are located near each other. Therefore, thearrangement may be slightly adjusted depending on the difference in arecording and reproduction direction between an opposite path disc and aparallel path disc. For example, in an opposite path disc, a secondrecording layer is accessed from the outer periphery to the innerperiphery. Therefore, a spare DL storing area in the second recordinglayer may be placed closer to the inner periphery than a defectmanagement area provided on the inner periphery.

Note that in the case of a multi-layered information recording mediumhaving at least three recording layers, the multi-layered informationrecording medium may store DL storing area management information inorder to manage the statuses of DL storing areas in a defect managementarea and a spare DL storing area. An example of DL storing areamanagement information is such that a value 0 is set when the DL storingarea is unused, a value 1 is set when the DL storing area is used, and avalue 2 is set when the DL storing area is determined to be defective.By storing such information for managing each DL storing area in a DDSarea, the DL storing areas can be efficiently managed.

Note that in Embodiment 1 a reference layer is the upper recording layerof a plurality of recording layer in the figures, though the referencelayer is not so limited and may be any of the recording layers uniquelydetermined under a predetermined rule. For example, a reference layermay be a recording layer of a plurality of recording layers which islocated at the shortest distance from the data read-out surface of amulti-layered information recording medium, or a recording layer whichis located at the longest distance from the data read-out surface.

Note that in Embodiment 1 the multi-layered information recording medium600 comprising two recording layers is described, though an informationrecording medium may comprise a larger number (at least 3) of recordinglayers. In either multi-layered recording medium, a defect managementarea is provided in any one of recording layers while a spare DL storingarea is provided in other recording layers.

Embodiment 2

Next, a multi-layered information recording medium according toEmbodiment 2 of the present invention will be described with referenceto the accompanying drawings.

FIG. 11 is a diagram showing a multi-layered information recordingmedium 800 according to Embodiment 2 of the present invention. Themulti-layered information recording medium 800 of Embodiment 2 comprisesa first recording layer 53 and a second recording layer 54. In the firstrecording layer 53 and the second recording layer 54, defect managementareas and spare DL storing areas are arranged in a manner similar tothat in the first recording layer 51 and the second recording layer 52shown in Embodiment 1. The multi-layered information recording medium800 is different from the multi-layered information recording medium 600of Embodiment 1 in that in the multi-layered information recordingmedium 800, the first recording layer 53 contains a head spare area 1101and an intermediate spare area 1102, and the second recording layer 54contains an intermediate spare area 1102′ and an end space area 1103.The sizes of these spare areas can be separately determined, however,for the sake of simplicity, it is assumed that all spare areas have thesame size (the size is indicated by the spare area size 713 (FIG. 12)).A data area 1100 is an area which contains a user data area 602 and theabove-described spare areas. Hereinafter, features of the multi-layeredinformation recording medium 800 different from the multi-layeredinformation recording medium 600 will be described.

The head spare area 1101, the intermediate spare area 1102, theintermediate spare area 1102′, and the end space area 1103 contain areplacement area. When a defective area is detected in the user dataarea 602, the replacement area may be used in place of the defectivearea. A defective area is herein a defective sector. A defective area A1110 and a defective area B 1112 each are a defective area in which userdata cannot be appropriately recorded and reproduced. The defective areaA 1110 is replaced with a replacement area A 1111 containing theintermediate spare area 1102. As a result, user data which was to berecorded in the defective area A 1110 is recorded in the replacementarea A 1111. Similarly, in a read operation, user data is read from thereplacement area A 1111 but not from the defective area A 1110.Similarly, a defective area B 1112 in the second recording layer 54 isreplaced with a replacement area B 1113 containing the head spare area1101 in the first recording layer 53.

Next, the contents of defect management information in Embodiment 2 willbe described with reference to FIG. 12. FIG. 12 shows locations of areasin a first defect management area 611 (DMA1). Hereinafter, only featuresof the first defect management area 611 (DMA1) of Embodiment 2 differentfrom Embodiment 1 will be described. A defect list 1209 stored in thesecond DL storing area 702 contains two defect entries, i.e., a defectentry A 1201 and a defect entry B 1202. The defect entry A 1201 isinformation indicating that the defective area A 1110 of FIG. 11 isreplaced with the replacement area A 1111. On the other hand, the defectentry B 1202 stores information indicating that the defective area B1112 of FIG. 11 is replaced with the replacement area B 1113. Therefore,a replacement status flag contained in the defect entry A 1201 and areplacement status flag contained in the defect entry B 1202 each are 0.This is because a replacement status flag has a value 0 when acorresponding defective area is replaced with a replacement area, andhas a value 1 when the defective area is not replaced and is registered.A defective sector layer number and a defective sector number indicate anumber which permits to identify a recording layer and a sector numberwhich permits to uniquely determine the location of a sector in arecording layer, respectively, as in Embodiment 1. The defective area A1110 and its replacement area B 1111 are both contained in the firstrecording layer 53, and therefore, a defective sector layer number 735and a replacement sector layer number 737 contained in the defect entryA 1201 both indicate 1. On the other hand, the defective area B 1112 iscontained in the second recording layer 54, and the replacement area B1113 is contained in the first recording layer 53. Therefore, adefective sector layer number 740 contained in the defect entry B 1202indicates a value 2 representing the second recording layer 54, and areplacement sector layer number 742 indicates a value 1 representing thefirst recording layer 53. Note that the replacement sector numbers 737and 742 represent a sector number which uniquely determines the startingposition of a replacement area in a recording layer as do the defectivesector numbers 735 and 740.

In Embodiment 2, the defective area B 1112 in the second recording layer54 is replaced with the replacement area B 1113 in the first recordinglayer 53. It is now assumed that, for example, a total of 1000 defectivesectors can be present in two recording layers. If defect management wasperformed separately for each recording layer, a spare area(s)corresponding to at least 1000 sectors has to be allocated in eachrecording layer. In other words, a spare area(s) corresponding to atotal of at least 2000 sectors is required for two recording layers. Onthe other hand, in Embodiment 2, a defect list for all recording layersis stored in a unified manner while a defective area in a certainrecording layer can be replaced with a spare area in another recordinglayer. Therefore, in the present invention, a spare area(s)corresponding to a total of 1000 sectors is required for the tworecording layers (e.g., 500 sectors are provided in each of the tworecording layers). Therefore, the volume of an area allocated as a sparearea can be reduced, thereby making it possible to increase the volumeof the user data area 602.

The multi-layered information recording medium 800 according toEmbodiment 2 of the present invention has been heretofore described.

As described above, the multi-layered information recording medium 800according to Embodiment 2 of the present invention will be describedbelow in terms of its effects in addition to the effects of the presentinvention described in Embodiment 1.

Defect management information relating to all recording layers containedin a multi-layered information recording medium is managed by a singledefect list, thereby making it possible to replace a defective area in acertain layer with a replacement area in a different layer. Therefore,even if defective areas occur intensively in a certain recording layerand all spare area in this layer are exhausted, spare areas in otherrecording layers can be used for replacement. Therefore, even ifdefective areas occur intensively in a specific recording layer due todegradation of a medium material or the like, spare areas in allrecording layers can be efficiently used and the reliability of recordeddata can be achieved. It is clearly appreciated that a method of using aspare DL in Embodiment 2 is the same as that in Embodiment 1, though adescription thereof is omitted.

Note that the disc medium of Embodiment 2 is an opposite path disc inwhich recording and reproduction are performed from the inner peripheryto the outer periphery of the first recording layer 53 and from theouter periphery to the inner periphery of the second recording layer 54.Similarly, in a parallel path disc in which recording and reproductionare performed from the inner periphery to the outer periphery in allrecording layers, defective areas can be similarly managed.

Embodiment 3

Hereinafter, an information recording/reproduction apparatus 500according to Embodiment 3 of the present invention will be describedwith reference to the accompanying drawings. The informationrecording/reproduction apparatus 500 performs recording and reproductionusing the multi-layered information recording mediums 600 and 800described in Embodiments 1 and 2, respectively.

FIG. 13 is a block diagram showing the informationrecording/reproduction apparatus 500 according to Embodiment 3 of thepresent invention. The information recording/reproduction apparatus 500comprises a disc motor 502, a preamplifier 508, a servo circuit 509, abinarization circuit 510, a modulation/demodulation circuit 511, an ECCcircuit 512, a buffer 513, a CPU 514, an internal bus 534, and anoptical head section 535. In the information recording/reproductionapparatus 500, the multi-layered information recording medium 800 isloaded. The optical head section 535 comprises a lens 503, an actuator504, a laser driving circuit 505, a photodetector 506, and a transporttable 507. Reference numeral 520 denotes a rotation detection signal.Reference numeral 521 denotes a disc motor driving signal. Referencenumeral 522 denotes a laser emission permission signal. Referencenumeral 523 denotes a light detection signal. Reference numeral 524denotes a servo error signal. Reference numeral 525 denotes an actuatordriving signal. Reference numeral 526 denotes a transport table drivingsignal. Reference numeral 527 denotes an analog data signal. Referencenumeral 528 denotes a binarized data signal. Reference numeral 529denotes a demodulated data signal. Reference numeral 530 denotes acorrected data signal. Reference numeral 531 denotes a stored datasignal. Reference numeral 532 denotes an encoded data signal. Referencenumeral 533 denotes a modulated data signal.

The CPU 514 functions as a control section. The CPU 514 controls theentire operation of the information recording/reproduction apparatus 500via the internal bus 534 according to an incorporated control program.As described below, the optical head section 535 can optically writeinformation in the multi-layered information recording medium 800 fromone side of the multi-layered information recording medium 800. Theoptical head section 535 can optically read information from themulti-layered information recording medium 800. The CPU 514 controlsexecution of a defect management process using the optical head section535 as described below.

In response to the laser emission permission signal 522 output from theCPU 514, the laser driving circuit 505 emits laser light 536 onto themulti-layered information recording medium 800. The light reflected bythe multi-layered information recording medium 800 is converted by thephotodetector 506 to the light detection signal 523. The light detectionsignal 523 is subjected to addition/subtraction in the preamplifier 508so as to generate the servo error signal 524 and the analog data signal527. The analog data signal 527 is A/D (analog/digital) converted by thebinarization circuit 510 to the binarized data signal 528. The binarizeddata signal 528 is demodulated by the modulation/demodulation circuit511 to generate the demodulated data signal 529. The demodulated datasignal 529 is converted by the ECC circuit 512 to the corrected datasignal 530 which does not include any error. The corrected data signal530 is stored in a buffer 513. The servo circuit 509 outputs theactuator driving signal 525 based on the servo error signal 524, therebyfeeding a servo error back to the actuator 504 for focusing control ortracking control of the lens 503. An error correction code is added bythe ECC circuit 512 to the stored data signal 531 which is an output ofdata from the buffer 513, so as to generate the encoded data signal 532.Then, the encoded data signal 532 is modulated by themodulation/demodulation circuit 511 to generate the modulated datasignal 533. The modulated data signal 533 is input to the laser drivingcircuit 505 so as to modulate the power of laser light.

The information recording/reproduction apparatus 500 may be used as aperipheral device for a computer, such as a CD-ROM drive or the like,along with the computer. In such a case, a host interface circuit (notshown) is additionally provided, and data is transmitted between a hostcomputer (not shown) and the buffer 513 through a host interface bus(not shown) such as a SCSI or the like. Alternatively, if theinformation recording/reproduction apparatus 500 is used as a consumerdevice, such as a CD player or the like, along with an AV system, an AVdecoder/encoder circuit (not shown) is additionally provided so as tocompress a moving image or sound or decompress a compressed moving imageor sound and the resultant data is transmitted between the host computerand the buffer 513.

In a reproduction operation of the information recording/reproducingapparatus 500 according to Embodiment 3 of the present invention, it isnecessary to provide two processes, a process of obtaining defectmanagement information and a process of reproducing sectors whileconsidering replacement, in order to reproduce information recorded inthe multi-layered information recording medium 800 comprising tworecording layers to which defect management of the present invention isapplied.

In a recording operation of the information recording/reproducingapparatus 500 according to Embodiment 3 of the present invention, it isnecessary to provide, in addition to the above reproduction operation,two processes, a process of updating defect management information and aprocess of recording sectors while considering replacement, in order torecord information in the multi-layered information recording medium 800comprising two recording layers to which defect management of thepresent invention is applied.

Hereinafter, an operation of the recording/reproduction apparatus 500 ofEmbodiment 3 will be described, in which recording and reproduction areperformed on the multi-layered information recording medium 800 ofEmbodiment 2 using defect management as described with reference to,mainly, FIGS. 11 and 12. A high level apparatus, such as a host computeror the like, outputs location information specifying an area whichrecording and reproduction are to be performed, which information isrepresented by a logical sector number (LSN). Physical locationinformation on the recording medium is represented by physical sectornumbers (PSNs). It is now assumed that a PSN contains a sector layernumber indicating a layer in which a sector is present, and a sectornumber with which it is possible to identify the location of a sector ina layer in which the sector is present.

FIG. 14 shows a flowchart 1400 for illustrating a procedure of obtainingdefect management information in Embodiment 3 of the present invention.

At the first step of the process of obtaining defect managementinformation, i.e., at step 1401, the CPU 514 instructs the servo circuit509 to control the focal point of laser light so as to follow a track ina reference layer.

At step 1402, the optical head section 535 reproduces a sector whichstores disc information, and the CPU 514 confirms parameters and aformat which are necessary for recording/reproduction of themulti-layered information recording medium 800.

At step 1403, the optical head section 535 reproduces a DDS area 700stored in a reference layer. The reproduced DDS data is retained in apredetermined place of the buffer 513.

At step 1404, the CPU 514 determines whether or not a DL starting layeris present in a reference layer, by referencing a DL start sector layernumber 711 in the DDS data within the buffer 513. If the DL startinglayer is present in the reference layer, the process proceeds to step1406. If the DL starting layer is present in a recording layer otherthan the reference layer, the process proceeds to step 1405.

At step 1405, the CPU 514 instructs the servo circuit 509 to control thefocal point of laser light so as to follow a track in a recording layerindicated by the DL start sector layer number 711.

At step 1406, the optical head section 535 reads a predetermined sizeportion of a defect list from a sector indicated by the DL start sectornumber 712. The read defect list is retained at a predetermined place inthe buffer 513.

FIG. 15 is a flowchart 1500 for illustrating a reproduction procedure ofsectors according to Embodiment 3 of the present invention, whereinreplacement is considered. In this reproduction process, assume thatdefect management information including DDS data and a defect list havealready been retained in the buffer 513.

At the first step of this reproduction process, i.e., at step 1501, theCPU 514 converts LSNs, which are assigned to respective areas to bereproduced, to PSNs (detailed descriptions of this step will bedescribed later with reference to FIG. 16).

At step 1502, the CPU 514 references to the layer number of the PSN ofan area to be reproduced to determine whether or not a recording layerin which the focal point of laser light currently exists is identical toa recording layer to be reproduced. If identical, the process proceedsto step 1504; if not, the process proceeds to step 1503.

At step 1503, the CPU 514 instructs the servo circuit 509 to control thefocal point of the laser light 536 so as to follow a track in arecording layer to be reproduced.

At step 1504, the optical head section 535 reproduces informationrecorded in a sector indicated by the PSN obtained at conversion step1501.

FIG. 16 is a flowchart 1600 for illustrating a procedure of convertingLSNs to PSNs (i.e., step 1501 of FIG. 15) according to Embodiment 3 ofthe present invention.

At the first step 1601 of this conversion process, LSN is converted toPSN without considering the presence or absence of replacement, i.e., ina manner similar to when no defective sector is present. Referring toFIG. 11, when the value of the ordinal level of a LSN to be converted issmaller than the number of sectors in the first user data area 15,

PSN=(Smallest PSN in the first user data area 15)+LSN.

When the value of the order of a LSN to be converted is greater than thetotal number of sectors in the first user data area 15,

PSN=(Smallest PSN in the second user data area 16)+LSN−(the total numberof sectors in the first user data area 15).

Note that since the multi-layered information recording medium 800 ofFIG. 11 has an opposite path track, a sector in the second user dataarea 16 to which the smallest PSN is assigned is located at theoutermost perimeter portion of the second user data area 16 (i.e., beingadjacent to the intermediate spare area 1002′).

At step 1602, the CPU 514 references defect entry data in a defect listto determine whether or not the PSN obtained in the above-described stepmatches a defective sector layer number and a defective sector numberstored in the defect list. If registered, the process proceeds to step1603; if not (i.e., no replacement), the process ends.

At step 1603, the CPU 514 selects a replacement sector layer number anda replacement sector number indicated by a defect entry (i.e., adefective sector layer number and a defective sector number) indicatingthe PSN from defect entry data registered in the defect list.

Note that when data is reproduced from the multi-layered informationrecording medium 600 (FIG. 6) having no spare area, the processindicated by step 1603 is omitted or the processes indicated by steps1602 and 1603 are omitted.

As described above, the information recording/reproduction apparatus 500according to Embodiment 3 of the present invention can reproduce datafrom a multi-layered information recording medium containing a defectmanagement area. The reproduction operation of user data which isperformed after the focal point of the laser light 536 has been moved toa recording layer to be accessed, is basically the same as thereproduction operation of user data performed for a single-layeredinformation recording medium. Thus, it is clearly appreciated that anyreproduction procedure for an information recording/reproducingapparatus designed for a single-layered disc can be used.

FIG. 17 is a flowchart for illustrating a procedure of updating defectmanagement information according to Embodiment 3 of the presentinvention. In this embodiment, as an example of a formatting process fora multi-layered information recording medium, initialization andupdating of defect management information will be described.

At the first step 1701 of the updating process, the CPU 514 produces DDSdata having predetermined definition values for a recording/reproductionapparatus and a defect list containing a DL header 720 in which thenumber of DL entries is set to be 0, in the buffer memory 513. In thiscase, a DL start sector layer number 711 and a DL start sector number712 in a DDS 700 before a formatting process (FIG. 12) are set in anewly produced DDS.

At step 1702, it is determined whether or not a recording layerindicated by the DL start sector layer number 712 is identical to arecording layer currently followed by the focal point of the laser light536. If identical, the process proceeds to step 1704; if not, theprocess proceeds to step 1703.

At step 1703, the CPU 514 instructs the servo circuit 509 to control thefocal point of the laser light 536 so as to follow a track in arecording layer indicated by the DL start sector layer number 711.

At step 1704, the CPU 514 records a newly produced defect list in anarea having a predetermined size which starts with a sector numberindicated by the DL start sector number 712. In this case, when a defectlist has been previously recorded in the area indicated by the DL startsector number 712 (e.g., the defect list 1209 (FIG. 12)), the previouslyrecorded defect list is updated to a newly produced defect list.

At step 1705, the CPU 514 determines whether or not data is correctlyrecorded in a DL storing area. If correctly recorded, the processproceeds to step 1707. If not (the area is not usable), the processproceeds to step 1706. The determination of the correctness of datarecording is carried out by reading data recorded in the DL storing areaand judging whether or not the read data is identical to data to berecorded.

At step 1706, the CPU 514 selects another usable DL storing area.Initially, the CPU 514 determines whether or not a defect managementarea (or a spare DL) of a recording layer, in which data is currentlyrecorded, contains a usable DL storing area. In the same recordinglayer, a DL storing area having a radial position close to that of acurrently used DL storing area is selected. If no DL storing area isusable in the same recording layer, the CPU 514 selects a usable DLstoring area containing an unused spare DL storing area in an adjacentrecording layer. The CPU 514 records a defect list, which has the samecontents as those of a defect list stored in a DL storing area which hasbeen determined to be unusable, in a newly selected DL storing area.

At step 1707, the CPU 514 determines whether or not a track currentlyfollowed by the focal point of the laser light 536 is of the referencelayer. If so, the process proceeds to step 1709; if not, the processproceeds to step 1708.

At step 1708, the CPU 514 instructs the servo circuit 509 to control thefocal point of the laser light 536 so as to follow a track in thereference layer.

At step 1709, the CPU 514 records the starting PSN of a DL area(containing a DL storing area selected in step 1706), in which a defectlist is recorded, in DDS data produced in the buffer memory 513.Specifically, a DL start sector layer number 712 and a DL start sectornumber 712 are updated.

At step 1710, the CPU 514 records the DDS data produced in the buffermemory 513 in a DDS area of a multi-layered information recording mediumusing the optical head section 535.

Note that in Embodiment 3, at step 1704, an area in which a defect listis recorded is not limited to a defect list storing area before aformatting process. It is clearly appreciated that, for example, alldefect list storing areas before a formatting process may be madeinvalid, and the CPU 514 may record a defect list in a newly designatedarea.

FIG. 18 is a flowchart 1800 for illustrating a recording procedureaccording to Embodiment 3 of the present invention, wherein replacementis considered.

At the first step 1801 of this recording process, the CPU 514 convertsLSNs, which specify sectors in which data is to be recorded, to PSNs(see FIG. 21).

At step 1802, the CPU 514 references to the layer number of a PSN todetermine whether or not a recording layer currently followed by thefocal point of the laser light 536 is identical to a recording layer inwhich data is to be recorded. If identical, the process proceeds to step1804; if not, the process proceeds to step 1803.

At step 1803, the CPU 514 instructs the servo circuit 509 to control thefocal point of the laser light 536 so as to follow a track in therecording layer in which data is to be recorded.

At step 1804, the CPU 514 records data in a sector indicated by the PSNobtained at step 1801 using the optical head section 535.

At step 1805, the CPU 514 determines whether or not the data recordingwas successful at step 1804. If successful, the process proceeds to step1807; if not, the CPU 514 determines that the sector in which it isattempted to record data is defective, and the process proceeds to step1806.

At step 1806, the CPU 514 allocates a spare sector for the sector whichis determined to be defective. The CPU 514 replaces the defective areawith an unused replacement area which contains a spare area at theshortest radial distance from the defective area and is present in arecording layer containing the defective area (in this case, thereplacement area is a spare sector). For example, when the defectivearea is detected on the outer periphery of the first recording layer 53(FIG. 11), a replacement area is allocated from the first intermediatespare area 1102 provided in the recording layer 53. If the intermediatespare area 1102 in the first recording layer 53 contains no usablereplacement area, a usable replacement area is allocated from theintermediate spare area 1102′ of the second recording layer 54. If theintermediate spare area 1102′ of the second recording layer 54 containsno usable replacement area, a usable replacement area is allocated fromthe head spare area 1101 of the first recording layer 53. In such asequence, any one of spare areas in a multi-layered informationrecording medium is assigned as a replacement area.

At step 1807, in the recording process, the CPU 514 determines whetheror not a spare sector has been newly allocated at step 1806. If not, therecording process ends; if so, the process proceeds to step 1808.

At step 1808, the newly allocated replacement sector is registered inthe defect list stored in the buffer memory 513. In this case, if thedefective sector is already registered in the defect list, only areplacement sector layer number and a replacement sector number areupdated. On the other hand, if a new defective sector is detected, thedetected defective sector is added to the defect list.

When data is recorded in the multi-layered information recording medium600 (FIG. 6) containing no spare area, the process indicated by step1806 is omitted. In this case, information which is used to manage thedetected defective sector is registered in the defect list.

As described above, the information recording/reproduction apparatus 500according to Embodiment 3 of the present invention can record data in amulti-layered information recording medium having a defect managementarea. In the present invention, a spare sector can be allocated from aspare area provided in a recording layer different from a recordinglayer in which a defective sector is present. The informationrecording/reproduction apparatus 500 can allocate spare sectors in amanner that gives a greater weight to reduction of a seek time or in amanner that gives a greater weight to reduction of the time required forsetting recording power. The recording operation of user data to theuser data area which is performed after the focal point of laser lighthas been moved to a recording layer to be accessed, is basically thesame as the recording operation of user data performed for asingle-layered information recording medium. Thus, it is clearlyappreciated that any recording procedure for an informationrecording/reproducing apparatus designed for a single-layered disc canbe used.

Although in the above descriptions of the present invention,reproduction/recording of information and defect management areperformed on a sector-by-sector basis, it is clearly appreciated thatthe present invention is applicable even when reproduction/recording ofinformation and defect management is performed on a block-by-block basis(a block contains a plurality of sectors), or on an ECC block-by-ECCblock basis (an ECC block is a unit based on which an error correctioncode of, for example, a DVD disc is calculated). Such a modifiedembodiment is made within the spirit and applicable range of the presentinvention, and any modified embodiment which is readily appreciated bythose skilled in the art, falls within the scope of the claims of thepresent invention.

Embodiment 4

Next, a multi-layered information recording medium according toEmbodiment 4 of the present invention will be described with referenceto the accompanying drawings.

FIG. 19 is a diagram showing a multi-layered information recordingmedium 1900 according to Embodiment 4 of the present invention. Themulti-layered information recording medium 1900 comprises two recordinglayers 55 and 56. The multi-layered information recording medium 1900comprises a user data area 1903 for recording user data. In Embodiment 4of the present invention, the upper recording layer (55) shown in FIG.19 is referred to as a first recording layer, and the lower recordinglayer (56) is referred to as a second recording layer.

The first recording layer 55 is located at a predetermined distance froma surface of the multi-layered information recording medium 1900 throughwhich data is read out (data read-out surface). The first recordinglayer 55 is referred to as a reference layer. This predetermineddistance is equal to a distance from the data read-out surface of anoptical disc comprising only one recording layer to the recording layer.A reference layer is predetermined among a plurality of recordinglayers.

The first recording layer 55 contains, from the inner periphery to theouter periphery along the recording/reproduction direction of themulti-layered information recording medium 1900, a lead-in area 1901, ahead spare area 1902, and a first user data area 1931 which is a portionof the user data area 1903. The second recording layer 56 contains, fromthe outer periphery to the inner periphery along therecording/reproduction direction of the multi-layered informationrecording medium 1900, a second user data area 1932 which is a portionof the user data area 1903, an end spare area 1904, and a lead-out area1905.

The lead-in area 1901 contains a control data area 1911 for storingcontrol information for the multi-layered information recording medium1900, and a first defect management area 1912 (DMA1) and a second defectmanagement area 1913 (DMA2) for recording defect management informationrelating to a defective area. The head spare area 1902 and the end sparearea 1904 contain a replacement area which may be used in place of adefective area in the user data area 1903. The lead-out area 1905contains a third defect management area 1921 (DMA3) and a fourth defectmanagement area 1922 (DMA4) for recording defect management informationrelating to a defective area. The first defect management area 1912(DMA1), the second defect management area 1913 (DMA2), the third defectmanagement area 1921 (DMA3), and the fourth defect management area 1922(DMA4) each store the same defect management information. This isbecause by duplicately recording the same defect management informationin a plurality of areas in the multi-layered information recordingmedium 1900, the reliability of the defect management information isimproved.

The user data area 1903 contains a first user data area 1931 and asecond user data area 1932. A defective area A 1915 is present in thefirst user data area 1931. A defective area B 1924 is present in thesecond user data area 1932. The defective area A 1915 is replaced with areplacement area A 1914. The defective area B 1924 is replaced with areplacement area B 1923.

The multi-layered information recording medium 1900 according toEmbodiment 4 of the present invention contains four defect managementareas having the same contents, thereby making it possible to obtain thereliability of defect management information. All of the four defectmanagement areas are provided intensively on the inner periphery of themulti-layered information recording medium 1900, thereby making itpossible to minimize a distance over the optical head section is moved.According to this feature, the time required for the initial process ofthe multi-layered information recording medium 1900 can beadvantageously reduced. Further, no defect management area is providedon the outer periphery, and therefore, the entire outer periphery of themulti-layered information recording medium 1900 can be used as a userdata area. Therefore, a larger user data capacity can be obtained.

A data structure of the first defect management area 1912 will bedescribed with reference to FIG. 20. As described above, the firstdefect management area 1912 (DMA1), the second direct management area1913 (DMA2), the third defect management area 1921, and the fourthdirect management area 1922 each have the same defect managementinformation. Here, only the first defect management area 1912 will bedescribed and a description of the other defect management areas isomitted.

FIG. 20 shows a data structure of the first defect management area 1912.A DDS area 2000, first to fourth DL storing areas 2001 to 2004, and a DLheader area 2020 have the same data structure as that of the DDS area700, the first to fourth DL storing areas 701 to 704, and the DL headerarea 720, respectively, shown in FIG. 7, and a description thereof isomitted. Here, a defect entry A 2021 and a defect entry B 2022 containedin a defect list 2009 will be described.

The defect entry A 2021 contains defect management information relatingto a defective area A 1915 (FIG. 19). The defective area A 1915 isreplaced with a replacement area A 1914. Therefore, a replacement status734 contained in the defect entry A 2021 indicates 0 which means thepresence of replacement. Since the defective area A 1915 is present inthe first recording layer 55, a defective sector layer number 735indicates a value 1 which means the first recording layer 55. Adefective sector number 736 indicates an identification number whichpermits to uniquely identify the defective area A 1915 in the firstrecording layer 55. Similarly, since the replacement area A 1914 ispresent in the first recording layer 55, a replacement sector layernumber 737 indicates a value 1. A replacement sector number 738indicates an identification number which permits to uniquely identifythe replacement area A 1914 in the first recording layer 55.

The defect entry B 2022 contains defect management information relatingto a defective area B 1924 (FIG. 19). The defective area B 1924 isreplaced with a replacement area B 1923. Therefore, a replacement status739 contained in the defect entry B 2022 indicates 0 which means thepresence of replacement. Since the defective area B 1924 is present inthe second recording layer 56, a defective sector layer number 741indicates a value 2 which means the second recording layer 56. Adefective sector number 741 indicates an identification number whichpermits to uniquely identify the defective area B 1924 in the secondrecording layer 56. Similarly, since the replacement area B 1923 ispresent in the second recording layer 56, a replacement sector layernumber 742 indicates a value 2. A replacement sector number 743indicates an identification number which permits to uniquely identifythe replacement area B 1923 in the second recording layer 56.

As described above, according to the multi-layered information recordingmedium 1900 of Embodiment 4, a larger user data capacity is obtained andthe performance of reading defect management information can beimproved.

Note that the disc medium of Embodiment 4 is an opposite path disc inwhich recording and reproduction are performed from the inner peripheryto the outer periphery of the first recording layer 55 and from theouter periphery to the inner periphery of the second recording layer 56.Similarly, in a parallel path disc in which recording and reproductionare performed from the inner periphery to the outer periphery in allrecording layers, defective areas can be managed.

Note that in Embodiment 4, two spare areas, i.e., the head spare area1902 and the end space area 1904 are provided in the multi-layeredinformation recording medium 1900, however, either or both of them maybe omitted.

Note that in Embodiment 4, for the sake of simplicity, the multi-layeredinformation recording medium 1900 having two recording layers has beendescribed, however, even in the case of a multi-layered informationrecording medium having at least three recording layers, theabove-described effect is obtained if a defect management area isprovided on the inner periphery of a reference layer and the innerperiphery of a recording layer other than the reference layer.

In the case of a multi-layered information recording medium having atleast three recording layers, a defect management area may be providedon the inner peripheries of all recording layers other than thereference layer.

Embodiment 5

Next, a multi-layered information recording medium according toEmbodiment 5 of the present invention will be described with referenceto the accompanying drawings.

FIG. 21 is a diagram showing a multi-layered information recordingmedium 2100 according to Embodiment 5 of the present invention. Themulti-layered information recording medium 2100 comprises two recordinglayers 57 and 58. The multi-layered information recording medium 2100contains a user data area 2103 for recording user data. The user dataarea 2103 straddles a boundary of the first and second recording layers57 and 58. In Embodiment 5 of the present invention, the upper recordinglayer (57) shown in FIG. 21 is referred to as a first recording layer,and the lower recording layer (58) is referred to as a second recordinglayer.

The first recording layer 57 is located at a predetermined distance froma surface of the multi-layered information recording medium 2100 throughwhich data is read out (data read-out surface). The first recordinglayer 57 is referred to as a reference layer. This predetermineddistance is equal to a distance from the data read-out surface of anoptical disc comprising only one recording layer to the recording layer.A reference layer is predetermined among a plurality of recordinglayers.

The first recording layer 57 contains, from the inner periphery to theouter periphery along the recording/reproduction direction of themulti-layered information recording medium 2100, a lead-in area 2101, ahead spare area 2102, and a first user data area 2131 which is a portionof the user data area 2103. The second recording layer 58 contains, fromthe inner periphery to the outer periphery along therecording/reproduction direction of the multi-layered informationrecording medium 2100, a second user data area 2132 which is a portionof the user data area 2103, an end spare area 2104, and a lead-out area2105.

The lead-in area 2101 contains a control data area 2111 for storingcontrol information for the multi-layered information recording medium2100, and a first defect management area 2112 (DMA1) and a second defectmanagement area 2113 (DMA2) for recording defect management informationrelating to a defective area. The head spare area 2102 and the end sparearea 2104 contain a replacement area which may be used in place of adefective area in the user data area 2103. The lead-out area 2105contains a third defect management area 2121 (DMA3) and a fourth defectmanagement area 2122 (DMA4) for recording defect management informationrelating to a defective area. The first defect management area 2112(DMA1), the second defect management area 2113 (DMA2), the third defectmanagement area 2121 (DMA3), and the fourth defect management area 2122(DMA4) each store the same defect management information. This isbecause by duplicately recording the same defect management informationin a plurality of areas in the multi-layered information recordingmedium 2100, the reliability of the defect management information isimproved.

The user data area 2103 contains a first user data area 2131 and asecond user data area 2132. A defective area A 2115 is present in thefirst user data area 2131. A defective area B 2124 is present in thesecond user data area 2132. The defective area A 2115 is replaced with areplacement area A 2114. The defective area B 2124 is replaced with areplacement area B 2123.

The multi-layered information recording medium 2100 according toEmbodiment 5 of the present invention contains defect management areason the inner periphery in the first recording layer 57 while containingdirect management areas on the outer periphery in the second layer 58,thereby dramatically improving the possibility that any directmanagement area on either the inner periphery or the outer periphery canbe used for reproduction even if a stain (e.g., a fingerprint or thelike) or a scratch is present on the multi-layered information recordingmedium 2100; and making it possible to obtain the reliability of defectmanagement information. Defect management areas are provided on only oneof the inner periphery and the outer periphery of each recording layer,thereby obtaining a larger usable area as a user data area. Therefore, alarger user data capacity can be obtained.

A data structure of the defect management area in Example 5 is the sameas that of Example 4 described with reference to FIG. 20, and adescription thereof is omitted.

As described above, according to the multi-layered information recordingmedium 2100 of Embodiment 5, the reliability of defect managementinformation can be improved while a larger user data capacity isobtained.

Note that the disc medium of Embodiment 5 is a parallel path disc inwhich recording and reproduction are performed from the inner peripheryto the outer periphery of the first recording layer 57 and from theinner periphery to the outer periphery of the second recording layer 58.Similarly, in an opposite path disc in which recording and reproductionare performed from the inner periphery to the outer periphery in therecording layer 57 and from the outer periphery to the inner peripheryin the recording layer 58, defective areas can be managed.

Note that in Embodiment 5, two spare areas, i.e., the head spare area2102 and the end space area 2104 are provided in the multi-layeredinformation recording medium 2100, however, either or both of them maybe omitted. If none of the spare areas are present in the multi-layeredinformation recording medium 2100, a defect list is used to manageinformation relating to a defective area with no replacement areaallocated.

Note that in Embodiment 5, for the sake of simplicity, the multi-layeredinformation recording medium 2100 having two recording layers has beendescribed, however, even in the case of a multi-layered informationrecording medium having at least three recording layers, theabove-described effect is obtained if a defect management area isprovided on the inner periphery of a reference layer and the innerperiphery of a recording layer other than the reference layer.

Embodiment 6

Next, a multi-layered information recording medium according toEmbodiment 6 of the present invention will be described with referenceto the accompanying drawings.

FIG. 22 is a diagram showing a multi-layered information recordingmedium 2200 according to Embodiment 6 of the present invention. Themulti-layered information recording medium 2200 comprises two recordinglayers 59 and 60. The multi-layered information recording medium 2200contains a user data area 2203 for recording user data. The user dataarea 2203 straddles a boundary of the first and second recording layers59 and 60. In Embodiment 6 of the present invention, the upper recordinglayer (59) shown in FIG. 21 is referred to as a first recording layer,and the lower recording layer (60) is referred to as a second recordinglayer.

The first recording layer 59 is located at a predetermined distance froma surface of the multi-layered information recording medium 2200 throughwhich data is read out (data read-out surface). The first recordinglayer 59 is referred to as a reference layer. This predetermineddistance is equal to a distance from the data read-out surface of anoptical disc comprising only one recording layer to the recording layer.A reference layer is predetermined among a plurality of recordinglayers.

The first recording layer 59 contains, from the inner periphery to theouter periphery along the recording/reproduction direction of themulti-layered information recording medium 2200, a lead-in area 2201, ahead spare area 2202, a first user data area 2231 which is a portion ofthe user data area 2203, a first intermediate spare area 2204, and afirst lead-out area 2205. The second recording layer 60 contains, fromthe inner periphery to the outer periphery along therecording/reproduction direction of the multi-layered informationrecording medium 2200, a second lead-in area 2206, a second intermediatespare area 2207, a second user data area 2232 which is a portion of theuser data area 2203, an end spare area 2208, and a second lead-out area2209.

The first lead-in area 2201 contains a control data area 2211 forstoring control information for the multi-layered information recordingmedium 2200, and a first defect management area 2212 (DMA1) and a seconddefect management area 2213 (DMA2) for recording defect managementinformation relating to a defective area. The head spare area 2202, thefirst spare area 2204, the second spare area 2207, and the end sparearea 2104 contain a replacement area which may be used in place of adefective area in the user data area 2203. The first lead-out area 2205contains a third defect management area 2216 (DMA3) and a fourth defectmanagement area 2217 (DMA4) for recording defect management informationrelating to a defective area. Similar to the first lead-in area 2201,the second lead-in area 2206 contains a control data area 2211 forstoring control information for the multi-layered information recordingmedium 2200, and a fifth defect management area 2221 (DMA5) and a sixthdefect management area 2222 (DMA6) for recording defect managementinformation relating to a defective area. Similar to the first lead-outarea 2205, the second lead-out area 2209 contains a seventh defectmanagement area 2223 (DMA7) and an eighth defect management area 2224(DMA8) for recording defect management information relating to adefective area. The first defect management area 2212 (DMA1), the seconddefect management area 2213 (DMA2), the third defect management area2216 (DMA3), the fourth defect management area 2217 (DMA4), the fifthdefect management area 2221 (DMA5), the sixth defect management area2222 (DMA6), the seventh defect management area 2223 (DMA7), and theeighth defect management area 2224 (DMA8) each store the same defectmanagement information. This is because by duplicately recording thesame defect management information in a plurality of areas in themulti-layered information recording medium 2200, the reliability of thedefect management information is improved.

The user data area 2203 contains a first user data area 2231 and asecond user data area 2232. A defective area A 2215 is present in thefirst user data area 2231. A defective area B 2225 is present in thesecond user data area 2232. The defective area A 2215 is replaced with areplacement area A 2214. The defective area B 2225 is replaced with areplacement area B 2226.

The multi-layered information recording medium 2200 according toEmbodiment 6 of the present invention contains defect management areason the inner periphery and the outer periphery in both the firstrecording layer 59 and the second recording layer 60, thereby making itpossible to obtain the reliability of defect management information. Forexample, the possibility that any direct management area on either theinner periphery or the outer periphery can be used for reproduction evenif a stain (e.g., a fingerprint or the like) or a scratch is present onthe multi-layered information recording medium 2100, is dramaticallyimproved, thereby enhancing the reliability of defect managementinformation. On the other hand, if a control circuit or an opticalsystem is affected by variations in temperature inside arecording/reproduction apparatus, the degradation of therecording/reproduction apparatus over time, or the like, the ability ofthe apparatus to perform recording and reproduction with respect to aspecific recording layer may be lowered. In such a situation, by storinga direct management area in all recording layers, it is possible toimprove the reliability of defect management information.

A data structure of the defect management area in Example 6 is the sameas that of Example 4 described with reference to FIG. 20, and adescription thereof is omitted.

As described above, according to the multi-layered information recordingmedium 2200 of Embodiment 6, the reliability of defect managementinformation can be significantly improved.

Note that the disc medium of Embodiment 6 is a parallel path disc inwhich recording and reproduction are performed from the inner peripheryto the outer periphery of the first recording layer 59 and from theinner periphery to the outer periphery of the second recording layer 60.Similarly, in an opposite path disc in which recording and reproductionare performed from the inner periphery to the outer periphery in therecording layer 59 and from the outer periphery to the inner peripheryin the recording layer 60, defective areas can be managed.

Note that in Embodiment 6, four spare areas, i.e., the head spare area2202, the first intermediate spare area 2204, the second intermediatespare area 2207, and the end space area 2208, are provided in themulti-layered information recording medium 2200, however, any or all ofthem may be omitted. If none of the spare areas are present in themulti-layered information recording medium 2200, a defect list is usedto manage information relating to a defective area with no replacementarea allocated.

Note that in Embodiment 6, for the sake of simplicity, the multi-layeredinformation recording medium 2200 having two recording layers has beendescribed, however, even in the case of a multi-layered informationrecording medium having at least three recording layers, theabove-described effect is obtained if a defect management area isprovided on the inner periphery and the outer periphery of a referencelayer and the inner periphery and the outer periphery of a recordinglayer other than the reference layer.

According to the multi-layered information recording medium of thepresent invention, control information areas, such as an area forstoring recording and reproduction parameters for the multi-layeredinformation recording medium, an area for storing information relatingto defect management, or the like, is provided in a single recordinglayer, thereby making it possible to access control information at highspeed.

According to the multi-layered information recording medium of thepresent invention, all defect management information for all recordinglayers is stored in a single recording layer, thereby making it possibleto access defect management information at high speed.

According to the multi-layered information recording medium of thepresent invention, a spare defect list storing area is provided in arecording layer other than a recording layer storing defect managementinformation, thereby making it possible to improve the reliability ofdefect management information.

According to the multi-layered information recording medium of thepresent invention, a disc definition structure area containinginformation indicating the location of a defect list and a spare defectlist area which may store the defect list are located at substantiallythe same radial positions, thereby making it possible to access thedefect list at high speed.

According to the multi-layered information recording medium of thepresent invention, all defect lists in all recording layers are managedin a unified manner, thereby making it possible to efficiently use adefect list area even if the incidence of defective areas varies betweeneach recording layer.

According to the multi-layered information recording medium of thepresent invention, a detected defective area is replaced with a sparearea in any recording layer, thereby making it possible to effectivelyuse spare areas and improve the reliability of data.

According to the multi-layered information recording medium of thepresent invention, a defect management area is provided on one of theinner periphery and the outer periphery of each recording layer, therebymaking it possible to obtain a larger user data capacity.

According to the information reproduction method and the informationreproduction apparatus of the present invention, it is possible toreproduce information from a multi-layered information recording mediumcontaining defect management information relating to a plurality ofrecording layer.

According to the information recording method and the informationrecording apparatus of the present invention, it is possible to recordinformation in a multi-layered information recording medium containingdefect management information relating to a plurality of recordinglayer.

Various other modifications will be apparent to and can be readily madeby those skilled in the art without departing from the scope and spiritof this invention. Accordingly, it is not intended that the scope of theclaims appended hereto be limited to the description as set forthherein, but rather that the claims be broadly construed.

1. A multi-layered information recording medium, comprising: a pluralityof recording layers; a user data area for recording user data, providedin at least two of the plurality of recording layers; a defect liststoring area for storing a defect list that is information for managinga defective area detected in the user data area; and at least one sparearea containing at least one replacement area, wherein when at least onedefective area is detected in the user data area, the at least onereplacement area may be used in place of the at least one defectivearea, wherein the defect list storing area is provided in a prescribedlayer of the plurality of recording layers, the defect list isinformation for managing a defective area detected in the prescribedlayer and a defective area detected in a recording layer other than theprescribed layer, at least one of the plurality of recording layersother than the prescribed layer comprises a spare defect list storingarea that is used to record the defect list when the defect list storingarea is not usable, and one of the at least one spare area is located inthe more inside circumference than the user data area of the one of theplurality of recording layers which is predetermined as a referencelayer.
 2. An apparatus for recording information in a multi-layeredinformation recording medium according to claim 1, the apparatuscomprises: a defect list recording section for recording the defectlist, wherein the defect list recording section records the defect listin the spare defect list storing area when the defect list storing areais not usable, and the apparatus replaces the defective area present inthe user data area with the replacement area contained in the at leastone spare area.
 3. An apparatus for reproducing information recorded ona multi-layered information recording medium according to claim 1, theapparatus comprising: a defect list reproducing section for reproducingthe defect list, wherein the defect list reproducing section reproducesthe defect list from the spare defect list storing area when the defectlist storing area is not usable, and the apparatus reproduces the userdata based on information which is reproduced from one of the at leastone spare area.